Water calculations for mash and sparge

First off, I am an all-grain newb so please keep my newbness in mind.

I read this:

RichBrewer said:

I have found that the most common thread here is not using enough water during mashing and sparging. All you need to do is figure 1 to 1 1/4 quarts of water per pound of grain for the mash and about 1/2 gallon of water per pound of grain for sparging.

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And figured out that for a 5-gallon batch of a Racer 5 IPA clone that has a 13.75 lb grain bill, I would need 4.45 gal for mash and 6.88 gal for sparge, or roughly 11 gallons of water total. This seems like an awful lot.

I also just downloaded Sparge Pal on my iPhone and I entered in the parameters for the same recipe, and it says I need 4.3 gal for the mash but only 4.7 gal for the sparge. Now we're down to 9 gallons which still seems like a lot of water.

First question - why the 2 gallon difference in sparge volume?

The recipe says to boil for 90 minutes and provides a hop schedule. I will obviously need a lot more than 90 minutes to boil off 4 or 6 gallons of water.

Second question - do I add the time needed to boil this much water to the beginning of the timeline? In other words, if the recipe says to add X amount of hops at the beginning of the boil, do I boil and start the hop schedule 90 minutes prior to the time I will reach the final 5 gallon volume?

Third question - do I really need to buy a kettle large enough to boil this much water? This doesn't seem right.

I use a bit more for mashing- generally 1.25-2 quarts per pound of grain is common- and I use 1.5 quarts/pound.

So, in a 13.75 grainbill, I would use 20.6 quarts, or 5.15 gallons.

A 13.75 pound grainbill should absorb +/- 1.5 gallons of water in the mash. That means you'd get out approximately 3.65 gallons of first runnings.

If you know you boil off 1 gallon an hour in the boil, and lose .5 gallons to trub/cooling shrinkage, you'd probably want to start with 6.5 gallons in the boil kettle.

The easiest way to figure sparge volume is by simple math. If you need 6.5 gallons in the boil kettle, and you will get out 3.65 gallons of wort in from the mash, you need to sparge with 2,85 gallons of sparge water. Call it three gallons, just in case! The iphone app sounds pretty close.

If you're flysparging, you just sparge up to your boil volume. If you're batch sparging, you measure your first runnings and then add the proper amount of sparge water based on that. In other words, if you want 6.5 gallons in the boil kettle, and you get 3 gallons out of the first runnings, you know that you need exactly 3.5 gallons of water in the sparge.

I start with 7 gallons, because I boil off 1.5 gallons per hour in my system and have about .25 gallons to trub loss. I like to start with 5.25 gallons in my fermenter, so I can keg 5 gallons of beer after fermentation ends.

Yooper is, as always, spot on!

To answer your question about why the difference between the two apps is because the software is probably using different calculations for the mash. As Yooper stated some people will go at 1.25 qts per pound, others may do 2qts per pound and in some cases people will go 1qt per pound and mash thick.

There are also assumptions being made about absorption, dead space in the kettle and mash tun which are volume losses and need to be calculated as well. If you have an idea of how your system works then you can fill in these blanks accordingly to fine tune your calculations.

As for the hop additions, if it is listed as a 60 minute addition you would begin your boil and run for the initial 30 minutes, then begin with the 60 and go forward from there.

Finally, if you are brewing a 5 gallon batch and need to start with 6.5-7 gallons of wort then you need a kettle large enough to handle that volume.

As an example: I brew 6.25 gallon batches on my system. Accounting for mash, runnings and dead space in tun and kettle I require 9 gallons of wort initially to wind up with 6.25 in my primary and then accounting for primary trub loss after fermentation my bottling volume is 6 gallons.

Hope this all helps and boy does Yooper type fast!

Thank you both for the helpful replies!